1. Field of the Invention
The present invention relates to a personal radio paging receiver and, more particularly, to a personal radio paging receiver which can prevent a noise disturbance mixed in power supplied from a DC/DC converter.
2. Description of the Prior Art
As shown in FIG. 1, a conventional personal radio paging receiver is constructed by an antenna 101 for receiving information, a radio section 102 for amplifying and demodulating the received signal, a control section 103 for processing the demodulated signal and performing notification, and a DC/DC converter 104. The DC/DC converter 104 supplies power to operate the control section 103. The DC/DC converter 104 has a primary battery 105 which operates as a DC power source. Power is supplied from the DC/DC converter 104 to the control section 103 during its operation. A voltage of about 2 V is required to operate the control section 103. In order to obtain this voltage, the DC/DC converter 104 having the circuit arrangement shown in FIG. 2 is used. More specifically, referring to FIG. 2, a transistor (TR) 404 is turned on/off by an oscillator (OSC) 405. While the TR 404 is ON, the energy is stored in an inductance 401. When the TR 404 is turned off, the energy is supplied to a capacitor 406 through a diode 402. Noise in a voltage V-out output upon this operation has the waveform shown in FIG. 3. That is, noise components A, B, and C are output upon switching of the DC/DC converter 104.
In this conventional personal radio paging receiver, since power containing noise is supplied from the DC/DC converter to the control section, harmonic components caused by noise are radiated within the control section or to the radio section, adversely affecting various electrical characteristics.